1. Field
The present invention relates to a secondary battery.
2. Description of the Related Art
Generally, a secondary battery is rechargeable, while a primary battery is unable to be recharged. The secondary battery is usable as an energy source in, for example, a mobile device, an electric vehicle, a hybrid vehicle, an electric bicycle, an uninterruptible power supply apparatus, and so on. A secondary battery can be used as a single battery or a battery pack having a plurality of batteries electrically connected as a one unit depending on an external apparatus usable with the secondary battery.